Soap or detergent rinsing agent



United States Patcnt O M Int. Cl. A471 15742; C11d 3/22 US. Cl. 252-442 Claims A'BSTRACT or THE DISCLOSURE A method of rinsing dishes so that the same are obtained from a mechanical dishwasher substantially free of spots and/or streaks, but without giving rise to overfoaming in the washer, comprising incorporating in the final rinse water 0.01 to 4 g./l. of a wetting'agent consisting essentially of an ester of a sugar and a fatty acid containing from 8 to carbon atoms.

This invention relates to dishwashing compositions. It more particularly relates to special compositions particularly useful in the rinsing of washed dishes.

In the hand washing of dishes, it has become a mark of superiority of the washing product (soap, detergent, etc.) that it make mountains of foamy suds. This has been and is an attribute of products of extreme desirability with respect to customer acceptance thereof.

With the advent of mechanical dishwashing, however, the criteria for customer acceptance of the dishwashing soap product has changed. The consumer has been subjected to heavy advertising with respect to so-called low-sudsing washing products. Besides the fact of customer acceptance, it has been found that excess suds, or even what would have been considered as a normal amount of suds, in a mechanical dishwasher is detrimental to the washing action of the machine. In fact, it is most desirable that washing and other agents used in mechanical dishwashers foam as little as possible since strong foaming reduces the mechanical cleaning action of vigorously churning water. Often high sudsing will cause a mechanical dishwashing machine to overflow and flood.

In order to overcome this problem, washing agent manufacturers have developed compositions and formulations which have little or no foaming or sudsing action under conditions of mechanical dishwashing.

It has been found that in mechanical dishwashers it is generally necessary and certainly expedient to conduct a washing-rinsing cycle of operations. This is accomplished by subjecting the dishes to a washing liquid which contains alkaline reaction agents in order to loosen and emulsify the residues of food on the dishes and silverware being mechanically washed. Upon completion of the washing, the alkaline agents are generally rinsed off with pure water.

It has been found desirable to provide a final rinse in which the rinsing medium has exceptionally good wetting power so that the final rinsing medium drains from the dishes substantially completely leaving few, preferably no, spots or streaks of rinse medium to dry as such on the dishes and no deposits of lime or other soiling agents which form a visible residue.

Compositions have been discovered which, when mixed with Water, form an adequate final rinse of accept- 3,481,881 Patented Dec. 2, 1969 able wetting power and leave dishes in relatively good spot-free condition. These compositions include' high molecular weight sulfates and sulfonates and non-ionic addition products of alkylene (e.g. ethylene or propylene) oxides to fatty alcohols, alkyl phenols and the like. It has been found, however, that in order to obtain the desired wetting action, such quantities of these materials had to be used as to produce excessive foaming in the dishwasher and subject it to overflowing, flooding and mechanical damage due to suds-clogging. It is possible to reduce the proportion of these compositions in the final rinse to a point where foaming is significantly reduced. However, at these low concentrations, it has been found that the wetting action of these compositions is significantly reduced to a point where it no longer can effect the substantially complete run-off of all potential soiling or spotting residues.

It is therefore an object of this invention to provide a novel wetting agent.

It is another object of this invention to provide a novel final rinse for mechanical dishwashing.

It is a further object of this invention to provide a novel mechanical dishwashing agent.

It is a still further object of this invention to provide a means of mechanically washing dishes to produce sparkling dishes without the inconvenience and potential hazard of substantial foaming.

Other and additional objects of this invention will become apparent from a full consideration of this entire specfication including the claims appended hereto.

In accordance with and fulfilling these objects, this invention comprises in one of its aspects the provision of a wetting agent suitable for use in the final rinse of mechanical dishwashing, comprising at least one ester of a sugar and a higher fatty acid. The esters of this invention are water-soluble and are in no way physiologically objectionable, at least in the small amounts left remaining on the dishes after drying.

The acid moiety of the esters of this invention include aliphatic carboxylic acids having about 8 to 20 carbon atoms in straight or branched chain. These acid moieties may be unsubstituted alkanoic acids or they may contain olefinic unsaturation therein and/or hydroxy substituents thereon. Preferably fatty carboxylic acids having about 10 to 18 carbon atoms and of the hereinbefore described configuration are used. Both monosaccharide and disaccharide esters are considered to be within the scope of this invention. Where the monosaccharide esters are chosen, it is preferred to employ fatty acids of the above description containing about 10 to 12 carbon atoms.

Exemplary of the suitable fatty acids within the scope of this invention are caprilic, capric, lauric, palmitic, stearic, oleic, linoleic and linolenic acids and their hydroxy substituted corresponding acids, such as ricinoleic, etc.

The alcoholic moiety of the esters of this invention comprises a naturally occurring or synthetic sugar. These sugars may be monosaccharides or disaccharides, as the case may be. Exemplary of the disaccharides which are useful in this invention are lactose, maltose, saccharose, as well as sugar mixtures obtained by the hydrolysis of starch, cellulose and other naturally occurring polysaccharide type material. Exemplary of the monosaccharides are glucose, fructose, xylose and other similar substances.

It is convenient to produce the esters to be used in this invention by straight acid-alcohol esterification or by rechlorisocyanurate, and were then substantially freed from the adherent alkaline liquid by an intermediate rinsing with clean water at 40 C. In the following final rinsing, different surface-active agents were employed, as set forth in detail in the table. In this final rinsing, water of 17 German hardness and a temperature of 75 C. was employed. On basis of the foaming properties and sparkle drying effects set forth in the table, the superiority of the agents in accordance with the invention can be clearly of the desired sugar in the presence of dimethyl formamide 10 noted.

tration, Sparkling gramsI- Drying Product liter Effect Foaming 0. 2 Machine foams over.

Dodecyl benzene ulfon ate 0. 05

0. 03 Large amount of foam. 0. 1 Machine foams over. Addition product of nonyl phenol and mols of ethylene oxide 0.05 d Do.

0. 03 Poor No disturbing foam. Sodium salt of lauryl alcohol diethyleue glycol monosulfuric acid ester 0. 05 Good Machine foams over.

0. 03 Poor... Large amount of foam. Addition product; of 4 mols of ethylene oxide m the polymer of 27 mols of propylene oxide {0. 2 do Disturbing foam.

0. 05 -...-d No disturbing foam. Monooleie acid saceharose ester 0.2 Good Machine foams over. 0. 05 do. N o disturbing foam. Monocaprie acid glucose ester 0. 4 do Do. gster from 1 mol of saceharose and 1 mol of the fatty acids obtained by sapomficatlon from coconut oil 0. 05 Excellent No disturbing foam.

itrie acid 1 Ester from 1 mol of maltose and 1 mol of the fatty acids obtained by saponification from beef tallow. 0. 2 -.do ...}No foam. Tartaric acid 0. 5

reaction medium or similar substances. The ester product can be recovered by known suitable chemical engineering purification procedures, such as extraction or distillation, preferably the latter under reduced pressure to minimize or avoid ester decomposition.

Exemplary of the sugar-fatty acid esters produced which are useful in this invention are saccharose monopalmitate, maltose ester of a mixture of fatty acids obtained by saponification of coconut oil, lactose monolaurate, glucose monocaprate, fructose ricinoleate, the esterification product of oleic acid with the hydrolysis product of starch (mostly maltose and glucose) and lactose dicaprate.

While it may be desirable in many cases to subject the sugar esters of this invention to purification to obtain the monomeric product containing predetermined appropriate mole ratios of each moiety, this is not always necessary and in many cases small quantities of di and polyesters, as well as unreacted sugar and even salt, are perfectly permissive impurities.

The wetting or rinsing agent sugar-fatty acid esters are generally used in a water solution in the final rinse formulation. It has been found suitable to use concentrations of 0.01 to 0.4 gram per liter, preferably 0.03 to 0.1 gram per liter of the ester in the final rinse bath. The quantity of ester in the final rinse bath should be adjusted to the salt content of the water, with somewhat larger quantities of ester used in combination with high salt content waters.

The wetting and rinsing agents of this invention can be used with hard or soft water, as the case may be. Where the rinsing water is hard, it is preferred to additionally include in the rinsing bath hydroxy carboxylic acids having about 2 to 5 carbon atoms. Exemplary of these hydroxy acids are tartaric, lactic, citric and glycollic acid. They may be incorporated into the final rinse bath in proportions of about 0.1 to 2 grams per liter, preferably 0.5 to 1 gram per liter, depending upon the degree of hardness of the water being employed.

The following examples are given by way of illustration and are in no way limiting upon the scope of this invention.

EXAMPLE In an ordinary commercial household dishwashing machine, normally dirty dishes were cleaned at 60 C. with a solution of an alkaline dishwashing agent containing 1 g./l. of washing agent consisting of 80% sodium tripolyphosphate, 19% sodium metasilicate and 1% sodium di- What is claimed is:

1. The method of rinsing dishes substantially spotless in a mechanical dishwasher operating under conditions of minimal foam which comprises providing in the final rinse water 0.01 to .4 g./l. of a wetting agent consisting essentially of an ester of a sugar and a fatty acid containing about 8 to 20 carbon atoms, and a lower hydroxy carboxylic acid containing about 2 to 5 carbon atoms wherein said hydroxy acid is present in a proportion of about 0.1 to 2 grams per liter.

2. A method as claimed in claim 1, wherein said ester is present in proportion of about 0.03 to 0.1 gram per liter.

3. A method as claimed in claim 1, wherein said acid contains about 10 to 18 carbon atoms.

4. A method as claimed in claim 1, wherein said acid contains about 10 to 12 carbon atoms and said ester is a monoester.

5. A method as claimed in claim -1, wherein said sugar is a member selected from the group consisting of lactose, maltose, saccharose, glucose, fructose, xylose and hydrolysis products of at least one member selected from the group consisting of cellulose and starch.

6. A method as claimed in claim 1, wherein said fatty acid is a member selected from the group consisting of caprilic, capric, lauric, palmitic, stearic, oleic, linoleic, and linolenic acids. "1

7. A method as claimed in claim 1, wherein said ester is a member selected from the group consisting of saccharose monopalmitate, maltose ester of a mixture of saponified coconut oil acids, lactose monolaurate, glucose monocaprate, fructose ricinoleate, sugars derived by hydrolysis of starch oleate, lactose dicaprate and maltose ester of a mixture of saponified beef tallow acids.

8. A method as claimed in claim 1, wherein said bydroxy acid is present in a proportion of about 0.5 to 1 gram per liter.

9. A method as claimed in claim 1, wherein said hydroxy carboxylic acid is a member selected from the group consisting of tartaric acid, lactic acid, citric acid and glycolic acid.

10. A wetting and rinsing agent consisting essentially of an aqueous solution of 0.01 to 0.4 g./l. of a sugar ester of a fatty acid, wherein said sugar is a member selected from the group consisting of lactose, maltose, saccharose, glucose, fructose, xylose and hydrolysis products of at least one member selected from the group consisting of cellulose and starch, and said fatty acid is selected from the group consisting of caprilic, capric, lauric, palmitic, stearic, oleic, linoleic, and linolenic acids and a lower hydroxy carboxylic acid containing about 2 to 5 carbon atoms.

References Cited UNITED STATES PATENTS 1,554,483 9/1925 Bailey et a1. 134-28 2,563,856 8/1951 McGinn 252-358 2,893,990 7/1959 Hass et a1. 260-234 2,954,347 8/1960 St. John et a1. 252-321 2,970,962 2/1961 Hass et a1. 252-135 6 3,024,229 3/1962 Hagge et a1 252-89 3,231,561 1/ 1966 Brunelle et a1. 252-89 OTHER REFERENCES 5 Martell: Chemistry of the Metal Chelates (1956),

Prentice-Hall Inc., pp. 541-544.

LEON D. ROSDOL, Primary Examiner 10 W. SCHULZ, Assistant Examiner US. Cl. X.R. 

